The A/C cooled OK but did not seem to dehumidify as it had in the past. Compressor seemed to cycle more often than before. Water droplets formed on the interior vent slots and dropped to the floor. The water drops became so numerous and regular that we had to put a bowl on the floor to catch the water. We nearly filled a cereal bowl full of water overnight and the cabin felt humid. I checked the A/C drain line on the interior of the unit and it was not leaking. I checked the outside drain and it was clear of obstructions and dripping and draining well.

When the "big" fifth wheel next door left the following day, the A/C unit seemed to return to normal operation and the interior leaking stopped completely.

Question: Since this was an older campground is it possible that I may have been experiencing a low voltage/power situation? If so, would low voltage/power cause the A/C unit to react as it did?

Low voltage should only put an additional load on the compressor and cause it to run hotter. The long term effect would be a failed compressor.

Was the fan running as normal and moving air. Low voltage may have effected the fan speed. I ask this because a lack of air across the evaporator would cause the surrounding parts of the AC to cool to the point of forming condensation that would not drip into the drain pan put just out on the floor. Are the filters clean?

If your trailer does not have a low voltage indicator on the AC get a voltmeter installed. They are cheap compared to a new AC. Try not to run the AC below 110 volts.

You may well be correct. The 50 amp plug box looked pretty old and beat up. The rest of the infrastructure of the campground looked pretty old, so the wiring may be the original wiring and never upgraded.

It was odd in that as soon as the "big" fifth wheel next to me left, the problem went away (less drain on the wiring ???). I hope that was indeed the problem. Since the unit returned to normal operation I hope that is an indication that no harm was done to the unit.